Metallic propeller.



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@ TTED S PIERRE JACOMY, F ASNIRES, FRANCE.

METALLIC PROPELLER.

Losaaso.

Specification of Letters Patent.

Patented Dec. 30, 1913.

Application filed August 12, 1912. Serial No. 714,696.

To all whom it may concern: Be it known that I, PIERRE JAcoMY, a

citizen of the French Republic, and resident at Asnires, France, haveinvented certam new and useful Improvements in Metallic Propellers, ofwhich the following is a specication.

- The present invention consists in light hollow metal propellers foraviation' or navithickness.

gation apparatus, offering the same advantages as those of wooden onesbut without the drawbacks of the latter. f

This invention consists in building hollow` propellers of a single pieceof metal with reduced ends, by stamping, rolling, drawing, bending orotherwise, and by means either of a plate soldered with its edges inbutt joint,or by means of a weldless tube.

-A construction of a hollow metal pro`l peller` according to theinvention is illustrated by way of example in the accompanying drawingin which- Figure 1 is an elevation of the propeller, and Fig. 2 showsthe different cross-sections made successively on lines 1 1 to 14.-14 ofFig. 1.

Accordingto this invention, aweldless metal tube a is used of givendiameter and After a .preliminary machining, this tube is worked on alathe or otherwise,

so as to reduce its two ends in a gradual manner, starting from a givendistance of the tube the said reduction taking place in accordance witha law given by the shape and the resistance to be given to the differentparts of the propellervfrom its center to the circumference. The tube athus machined is stove in transversely from one side to the other,without removing any material, that is to say, provided with twodiametri- Ically opposite openings, the edges b of which are bentinward. This arrangement insures a very great resistance of the pro-lpeller at its central portion. Through the openings thus produced isintroduced a sleeve c which is secured by autogenous welding or in someother way, to the edges of the openings in question, and constitutes thehub proper of the propeller. This sleeve c is bored in a conical,polygonal or cylindrical shape, according to the cross-section of thespindle intended to receive the propeller.

At each side of the hub b, the tube a is shaped by crushing it on stampsand mandrels or in any other way, so as to give to the two portions ofthe said tube such helical and curved shapes as may be desired inaccordance with the pitch and diameter adopted. The closely adjoiningtwo lips forming the ends of the blades, are then soldered together, andthe whole of the propeller is then polished.

The propeller thus constructed, has no solution'of continuity, no jointof any sort and consequently offers the greatest possible resistance tothe combined efforts of centrifugal force, of resistance of the Huid inwhich it acts, and also of the vibrations of the engine. It is as lightas a wooden propeller, and has over the latter the advantage of agreater resistance to shocks when the dimensions are equal. The samehollow light metal propeller in a single piece, can be made from a steelplate or' a plate of any other suitable metal, the variable thiclmess ofwhich, decreasing from a given central line, could be obtained by arolling or in any other way. This sheet or plate'is afterward shaped bysuccessive passages or stages in suitable matrices, gradually bringingit to the final helical shape. The edges of the plate are in that methodof manufacture broughtagainst each other and then soldered, preferably`ytoward the rear edges of the blades of the propeller.

Although this latter meth'od of manufacture is in accordance with theprocess for building a light hollow metal propeller according to thisinvention, it 1s preferable to use the method of manufacture in whichthe said propeller is made from a tube as hereinbefore described.

What I claim as my invention and desire to secure by Letters Patent isl 1. A light hollow 1metallic propeller made of a single piece of metaland comprising at the center openings with stamped out odge receiving asleeve.

2. A hollow metallic propeller made of a single weldless tube with edgesor ends of 'Q v n 1,082,750

a, decreasing cross-section decreasing on both sides of a given centralline, said ends being 4formed into helical blades comprising at the'center openings receiving a sleeve.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

PIERRE JACOMY.

Witnesses: A

VICTOR DUPONT, H. C. CoXE.

